regs for Maximum supply cable lenght between the main supply and a protective device

[Gosport_Cavalie]

Is anyone aware of any UK regs that describe the maximum length of a supply cable between the main supply and a protective device such as an RCD in an industrial installation?

I ask this because I have come across what I am sure is a dangerous installation at work but need the regs to back me up when I report it, the installation is as follows.

we have a 240V 16A bs4343 type industrial socket (blue 3 pin round type) mounted in a cab, this socket is fed from an RCD 16A 30ma mounted inside the cab directly behind the socket with 2.5mm tri rated cables, my concern is the fact that the cable supplying the RCD is also 2.5mm tri rated and is about 7 ft long but it goes to a 100A supply which means this 2.5mm cable rated to carry 30A has a potential fault current of 100A.

To me this is both dangerous and illegal, now to carry 100A this cable should be at least 16mm but this would not fit into the RCD. I believe that the supply should go from the 100A supply in 16mm cable to an MCB rated at 16A and then you could supply the RCD on a 2.5mm cable.

I have disconnected this circuit.

The person who installed this circuit will be facing dismissal so I need to be right.

 

[Jimmyb]

Re: regs for Maximum supply cable lenght between the main supply and a protective dev

think its 3meters but not 100% sure

 

[yellowvanman]

Re: regs for Maximum supply cable lenght between the main supply and a protective dev

read:
433.2.1 & 433.2.2

in addition circuit should not be protected by an RCD only, some form of overcurrent protection should be in place.

 

[Knobhead]

Re: regs for Maximum supply cable lenght between the main supply and a protective dev

This is an industrial situation so be very careful before you start quoting BS7671 in a disciplinary case. You’ll most likely be shot out of the water with an unfair dismissal case.
One glaring failing is the socket is not fused. It’s quite common to fit a clearly marked BS1363 RCD protected socket wired to the incoming side of a panel allowing work to be carried out with the main switch off.

 

[Deleted member 26818]

Re: regs for Maximum supply cable lenght between the main supply and a protective dev

Yes Regulations 433.2.1 & 433.2.2, as yellow van man has pointed out.

 

[Chr!s]

Re: regs for Maximum supply cable lenght between the main supply and a protective dev

Is anyone aware of any UK regs that describe the maximum length of a supply cable between the main supply and a protective device such as an RCD in an industrial installation?

I ask this because I have come across what I am sure is a dangerous installation at work but need the regs to back me up when I report it, the installation is as follows.

we have a 240V 16A bs4343 type industrial socket (blue 3 pin round type) mounted in a cab, this socket is fed from an RCD 16A 30ma mounted inside the cab directly behind the socket with 2.5mm tri rated cables, my concern is the fact that the cable supplying the RCD is also 2.5mm tri rated and is about 7 ft long but it goes to a 100A supply which means this 2.5mm cable rated to carry 30A has a potential fault current of 100A.

To me this is both dangerous and illegal, now to carry 100A this cable should be at least 16mm but this would not fit into the RCD. I believe that the supply should go from the 100A supply in 16mm cable to an MCB rated at 16A and then you could supply the RCD on a 2.5mm cable.

I have disconnected this circuit.

The person who installed this circuit will be facing dismissal so I need to be right.

What Happens if your wrong, do you get the sack?

There is a Reg which allows this set up, read 433.2 to see if it comply's, you may need to eat humble pie lol

Regards Chris

 

[Silly Sausage]

Re: regs for Maximum supply cable lenght between the main supply and a protective dev

Deleted due to incorrect assumption.
Note to self, read the OP properly!

 

[Engineer54]

Re: regs for Maximum supply cable lenght between the main supply and a protective dev

The person who installed this circuit will be facing dismissal so I need to be right.

Are you being used by any chance to find reasons to dismiss this guy?? If you are your on very sticky ground here, that could come back and bite You!!

 

[Knobhead]

Re: regs for Maximum supply cable lenght between the main supply and a protective dev

GC go away and start reading, dismissal procedures should take you 6 months to start with. You’re trying to base a case on regulations that are inapplicable to the situation. If the warm smelly stuff hits the fan, you’ll be first in line for it!
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